1. Field of the Invention
The invention relates to a one-piece header assembly for connecting an implantable medical device to a body organ intended to be assisted by the medical device. The header assembly includes a feedthrough assembly that is hermetically welded onto a base plate, which is subsequently welded to the medical device.
2. Description of Related Art
Header assemblies for implantable medical devices generally comprise feedthrough conductors in the form of pins or wires connected to the internal components of the medical device. The feedthrough wires extend through a wall of the medical device housing, such as a lid, and are electrically insulated there from by a ceramic-to-metal seal, and the like. Electrical continuity is established by connecting intermediate conductor wires between the feedthrough wires and connector blocks in the header assembly. Examples of this type of header assembly are shown in U.S. Pat. No. 4,254,775 to Langer, U.S. Pat. No. 4,262,673 to Kinney et al., U.S. Pat. No. 4,764,132 to Stutz, Jr., U.S. Pat. No. 5,282,841 to Szyszkowski and U.S. Pat. No. 5,336,246 to Dantanarayana, the disclosures of which are incorporated herein by reference. The intermediate conductor wires of the implantable medical devices disclosed in these patents represent electrical connections that could fail through improper connection, corrosion, breakage, and the like.
More recently, U.S. Pat. No. 7,069,081 to Biggs et al., which is assigned to the assignee of the present invention and incorporated herein by reference, describes a header assembly attachable to a medical device for the purpose of connecting its output terminals to at least one lead, the lead terminating at a target organ or portion of the body intending to be assisted. A number of leads are connectable to the header, including single and coaxial leads. The header assembly may be molded directly to the medical device or preformed and then attached to the device casing, either by mechanical fasteners and/or chemical adhesive.
These header assemblies require either a backfilled liquid sealing material to be dispensed between the bottom side of the header assembly and the upper lid of the implantable device, or complex mechanical fasteners to firmly secure the header assembly to the device, or both. These features increase device cost and manufacturing cycle time, while the sealing connection between the header assembly and the device is still less reliable than desired.
Accordingly, there remains a need for a header assembly that can be quickly and simply manufactured, and that can be joined to an implantable device in a long lasting hermetic seal without sealant backfilling or complex fasteners.